1) Field of the Invention
The present invention is directed to internal combustion engines and in particular to controlling the power output, increasing the fuel efficiency and reducing the emissions of an internal combustion engine.
2) Description of Prior Art
Conventional systems to control the power output of a spark ignition internal combustion engine restrict the flow of the fuel/air vapor allowed to enter the combustion chamber. These systems result in the maintenance of a substantial vacuum that is a function of engine displacement for a given power output. This vacuum, maintained at a given rate of gas flow, represents wasted energy.
In Asayama (U.S. Pat. No. 4,614,175), a control system is provided to optimize the use of exhaust gas recirculation as part of a conventional emission control system. The focus of this reference is the use of certain sensors to ascertain the operating condition of the engine; thereby, optimizing performance and reducing emissions. In Gartner (U.S. Pat. No. 5,669,365), a method is provided for the reduction of accumulated exhaust particles that tend to clog heat exchangers.
In Kerjean (U.S. Pat. No. 6,250,291), a method is provided for reducing unwanted tailpipe emissions resulting from transient operations of a traditional Exhaust Gas recirculation (EGR) system. The method involves the use of an oxygen sensor and a fuel/air control device that optimizes the mixture of air and fuel delivered to the engine during the transition into/out of EGR. The focus of the cited reference is the ability to extend a low emission operation that is obtained when a properly adjusted engine is operated at a steady-state to the region of operation where the engine load/speed changes due to road requirements. During such time, it is expected that the emission control systems (such as the EGR system) must quickly adjust in order to optimally limit tailpipe emissions.
In Nishada (U.S. Pat. No. 4,727,849), a control system is provided that utilizes an oxygen sensor located such that the proportion of oxygen available in the engine's intake mixture can be ascertained during the operation of a traditional Exhaust Gas Recirculation system. During operation, a small amount (relative to the total atmospheric gas input) of exhaust gas is recirculated into the engine input (what is normally the air/fuel inlet) in order to reduce emission of oxides of nitrogen. The reduction of nitrogen oxide occurs due to the cooling effect such inert gas has upon combustion. Present day automobile engines control the amount of fuel mixed into this input gas based upon the expected effect that recirculated exhaust gas has upon combustion. The reference; thereby, provides a method for sensing the amount of oxygen present within the input gas flow and using this information to optimally improve combustion and tailpipe emissions.
Paas (U.S. Pat. No. 5,785,030) relates to the use of Exhaust Gas Recirculation in diesel engines by providing a method for reducing soot that accumulates upon the surfaces of components such as heat exchangers.
The prior art references do not provide an effective method for improving overall thermal efficiency; reducing the intake vacuum of the internal combustion engine; or effectively using an exhaust gas recirculation system to control engine power output. In regard to the wasted energy, it is desirable to have a system and method of use to control the power output of an engine while avoiding the maintenance of a vacuum and reducing undesirable emissions in the exhaust of an internal combustion engine.